PNNL

Abstract

Proteomic and lipidomic profiling was performed during multiple time-points of acute HCV infection of cultured Huh-7.5 cells to gain new insights into the intracellular processes influenced by HCV infection. Our proteomic data suggest that HCV induces early perturbations in glycolysis, the pentose phosphate pathway, and the citric acid cycle that favor host biosynthetic activities supporting viral replication and propagation. This is followed by a compensatory shift in metabolism aimed at maintaining energy homeostasis and cell viability during elevated viral replication and increasing cellular stress. Complementary lipidomic analyses identified numerous temporal perturbations in select lipid species (e.g. phospholipids and sphingomyelins) predicted to play an important role in viral replication and down-stream assembly and secretion events. The elevation of lipotoxic ceramide species suggests a potential link between HCV-associated biochemical alterations and the direct cytopathic effect detected in this in vitro system. Using innovative computational modeling approaches we further identified novel topological protein bottlenecks that are essential for HCV-associated metabolic reprogramming. Significantly, these protein bottlenecks represent mitochondrial fatty acid oxidation enzymes present among a subset of host cell metabolism proteins comparably regulated during in vitro infection and in liver tissue from HCV-infected patients with histological evidence of fibrosis. Collectively, these data suggest that HCV-associated targeting of bottleneck proteins functioning in mitochondrial fatty acid oxidation may play a key role in regulating the temporal alterations in cellular metabolic homeostasis that occur during infection and that related physiological disruptions may contribute to liver disease progression.